The Disintegration Mechanism
by romantiscue
Summary: You will grant him a kunoichi-style execution. One-sided Uchihacest, non-explicit. Darkish. Twisty.


**begin the begin**

You prepare for almost two years, scouring Orochimaru's notes on the subject and reading stolen Uzumaki scrolls on seals until you have what you need to commit fully to the course of action you've chosen. How to reverse this. How to unmake the cycle. How to cut the möbius band of your and your brother's entangled lives. To avenge the clan and yourself and the life that was stolen from you.

You know his reasons now, in Madara's words, but it only makes room for hollowness where before the core of your anger was a lump of festering, infected hatelove. (He hadn't needed to kill the Uchiha children, the infants. They'd had no part in it. _Psychotic loyalty_, you'd thought, _and to what? Konoha? _Or perhaps to you, but that's a thought too sharp-edged to touch. You do not want to be his justification for slaughter.)

You're finally back, but the life in Uchiha complex almost kills you. The presence of your father, your mother, your _everyone_ crackles in your chest like an explosion just waiting to go off, warming the blood in your veins and sucking the breath from your lungs. For weeks, you walk about the compound and its people with that explosion frozen in your chest. A scream claws at your throat every time you open your eyes and ceiling of your childhood room stretches out above you instead of the star-splattered sky you left behind.

But you are shinobi. You adapt. You don't flinch at your mother's touches or your father's stern admonishments. You meet your brother's eyes.

Stopping the uprising is almost too easy, if only because you know every twist and turn that led up to that eventual decision to turn the Uchiha into a clan of traitors. You'd pieced it together with your father's journal entries and Sandaime's own timeline of events. Small changes, that was all. And as you grew, the clan was still discontent, but never came close to making that fatal decision. And they never realize why their path had changed, or even that it had changed at all.

You chose your way, months after meeting the too-young Itachi. The easiest way. The most painful way. Instead of the kindness of an assassination, you would grant a traditional kunoichi-style execution that would take weeks to complete. Because you'd never known, and the feeling that you really should have was something you couldn't force away. Itachi's eyes on you, warm and tender and gentle and _more_. Not just brotherly in his affection.

You hit ten and that's where those looks warmed beyond what you remembered. Perhaps it should have scared you, repulsed you, but somehow you're not surprised at all. Like you knew all along there might have been something more, somewhere in the fathomless depth of your brother's feelings for you.

That night, when he bids you good night, you give him a kunoichi's smile and embrace him like a serpent. Slither your arms around his waist and squeeze in closely, align your chest and hips with his for just a moment. Then you lean back and give him a little brother smile, wave good night into Itachi's bemused face and close your bedroom door behind you.

You smile a knife's smile into your pillow.

**how to create a catalyst**

You look up when your brother enters the kitchen, greeting him happily before dipping your spoon back into the porridge. Itachi has stopped in the doorway and is observing you, looking for clues as to what really happened yesterday. You know he's thinking that he must have imagined it, and that his own response to that fleeting moment was not what it had _felt_ like when it was happening.

"Did you have a good night's sleep, Sasuke?" he asks as he seats himself opposite you, and you nod with a mouth full of porridge. His gaze rests upon you with a tenderness that slices your insides like a fine blade. But this was never about right or wrong. As it always is, it's about revenge. Your heart pumps cold blood through your veins.

"Nii-san," you ask after a few minutes of easy silence where you finish your porridge and your brother takes delicate sips of his coffee. "I was wondering..." you trail off, make sure to look uncomfortable, and like an actor waiting for a cue, Itachi tilts his head.

"Yes?" Always willing to give anything to ease your way, whether it's a gentle prompt or a head full of torture. You look up through your fringe and then squirm.

"Yesterday my sensei lectured us on something, but I didn't really understand everything," you say, and it's true, and it's what you've been waiting for. Itachi looks politely attentive, leaning forwards to show you that he's listening, that he's focused on you.

In this life, you've never doubted that you are the sole focus of your brother's attention whenever he looks at you. "It was about," you hesitate, like you're embarrassed, "It was about sex." You wait for Itachi's expression to strain, but he exceeds your expectations; it doesn't flicker in the slightest. Instead he puts down his cup, and nods. Encouraging.

"They were talking about, eh, sex on missions," you trail away in apparent embarrassment, and poke at your porridge.

"You know you can ask me anything, Sasuke," Itachi says quietly when it becomes apparent that your words are locked away from you. You look up through your fringe, considering. Itachi waits.

"How do you prepare for that?" bursts out of you, like you hadn't entirely meant to say the words out loud. You hunch your shoulders immediately, like you think you've gone too far, and watch through your lashes as Itachi pushes his cup aside.

"You study for it." Itachi pauses, looks pained for a brief moment. "Of course, only experience can give you an accurate image of mission intercourse," he says and you has to admire him for not tripping over that last word. Your brother pauses again, tilts his head to the right. "Why are you worried about this now, Sasuke? Genin teams don't take missions expected to include anything sexual." He's watching you closely, and goosebumps tickle the back of your neck.

You shrug halfheartedly, and from half-slit eyes watch your brother's slim fingers tighten around each other. "Has your team leader suggested anything of the sort?" he asks in a carefully smooth voice. You let your shoulders tense, knows by the way Itachi's knuckles whiten as his hands squeeze harder on each other, and then relaxes again. "Perhaps he is in need of a quick reminder of the duties and expectations of genin teams."

You look up with wide, panicked eyes. "No! Brother, you can't tell him I told you! I'm not supposed to talk about missions to other shinobi!" Then you flush. "I mean, I wasn't going to tell anyone else. But you're you and..." you fidget, tug at your hair. That makes your brother's anger catch and falter, as you knew it would.

None of what you are saying is a lie. Not one word. And yet it isn't the truth, because you didn't lose your sharingan when you came back. You didn't lose your ability to weave genjutsu through an unguarded mind like your jounin-sensei's. To mention the possibility of a 'body work' mission, hint that it may lay in your future. When Itachi goes to investigate, all he'll find is that the jounin thought it would be a quick way to shut up the other two members of your team – how was he suppose to know you'd snatch it up, that it would worry or even scare you?

"Have you done missions like that, nii-san?" you ask then, hesitant. Itachi nods, hawk eyes on your face to gauge your reaction. He wants anything but to frighten you. "What was it like?" you ask quietly. All he'll see in you is worry, a need for reassurance and perhaps a very faint sort of curiosity.

"The first time you perform a mission is always unpleasant," Itachi says slowly, weighing his words with care. "But as you become used to it, you develop strategies to deal with the experiences."

"And then it stops hurting?" you ask, biting your lip and looking down. You feel more than see your brother flinch, because it is a rapidly smothered involuntary movement and Itachi had always been very quick.

"Hurting?" Your brother's voice is smooth and gentle enough to be smoke in your ears. He must be good at coaxing witnesses to talk, you think.

But this is not the direction you wish for this conversation to move, so you smooth your fringe down and rush your next words. "Only, I tried it in the shower yesterday and -" you watch from beneath your lashes as the quickly-spoken sentence punches the air out of Itachi's lungs. His eyes widen and that shuts you up. You flush harder, and your eyes slant to the side, like you're ashamed.

That thaws his reaction, and it hits you then that this is like a dance. You know the steps, because your brother circles around you in a way that makes him predictable to you. In these circumstances. He still seems out of sorts though, as you'd hoped, and when he says, "Tried it?" there is a ripple in his voice.

"Sensei said some things, and uhm. I thought I should try. But it just hurt." Your voice is very quiet and uncertain and your brother looks like he's a second away from having a more visible kind of reaction. You wonder if, under the table and out of your sight, his pants have tented over his crotch.

"That's," you watch his Adam's apple bob through your lashes, "- understandable, Sasuke. Little brother. You're too young for-" he hesitates here, briefly, but you see it anyway, "that kind of of activity." Is he speaking to himself, you wonder, trying to convince himself of his own words? No, you think a second later, Itachi already knows. But even geniuses need the occasional reminder, no matter how firm their self-restraint.

You purse your lips, as if in thought, then nod. "Okay, brother."

And suddenly Itachi looks exhausted, like he's holding himself upright by the skin of his teeth. You smile sweetly, thanking him for his advice and when he gets up to leave a few minutes later, his shoulders are slumped and tensed.

It's that word. _Brother._ A reminder.

**this is a rehearsal**

You stand half-hidden by a tree in the courtyard and watch your brother move through katas with the grace of a cat, or a bird in flight. You know he's noticed you, because his movements have slowed and smoothed. With a private smile, you wonder if he's performing for you. Wanting to look his best.

You know he won't call out to you, because that moment in the kitchen yesterday is on his mind. Perhaps it was also in his dreams last night.

"Nii-san?" you say, finally, and Itachi throws a glance your way. If you hadn't already known that he'd seen you, that complete lack of surprise would have told you you'd been noticed.

Itachi stops, gives you a faint smile. His eyes are warm, and they are hesitant. You linger behind the tree no more; move towards him instead, lean in for a hug. Because it is something you want, Itachi's wiry arms wrap around you, no matter that he might have preferred to move away this one time.

Both you and your brother use the morning workout routine to process happenings of yesterday, and you know where his mind has lingered since dawn.

"Sasuke? Weren't you suppose to meet with your team today?" Itachi asks, and you shake your head no. You graduated a year early this time around, and your team is nothing to you. They're not the purpose of your life.

You lock your fists in your brother's shirt, and his hands rise up to smooth over your shoulders. There is a sense of uncertainty in the movement, and though that uncertainty was what you were aiming for, you cannot stop the feeling of wrongness it causes you. Itachi is anything but uncertain. It annoys you that you can make your larger-than-life brother, your past life's most recurring nightmare, feel this way.

It also elates you.

"Help me practice?" you ask, leaning away from Itachi's body to beam into his face. That gentle smile graces your brother's fine features again, and he nods. For once, he has time for you. Maybe as penitence for unwelcome thoughts.

"What did you want to practice, little brother?" You pretend to think, but in reality you decided what to ask for the moment this opportunity presented itself.

"The cat katas," you say, nodding decisively. There is a flash of something dark in your brother's eyes, something you shouldn't be able to catch at this age. The cat katas require extensive body contact to be taught properly. You wonder if this is the moment where Itachi is going to poke your forehead, and tell you 'another time, Sasuke'.

It is not. Instead his smile gentles further, and whatever darkness shaded his eyes is carefully tucked away, like a blade in a sheathe, or perhaps like fragile glass into protective velvet cloth.

It begins easily, your brother merely pointing to where your knees aren't bent enough or your elbow is too sharp. But you won't let him get away: you make a mistake. Then another, of a similar kind. Turning what should be a precise bend of your hip into a clumsy twist of your waist, instead.

It is not enough for him to point out the mistake, and he notices that you are growing frustrated with his instructions. When he steps behind you, it is only as a last resort, only because he does not want you to leave him behind in anger. His hands are still hesitant, more so now that they rest lightly on your waist.

"Like this," he says, gently guiding you through the movement. You bend to the light pressure his hands exert and arrange your face into a grimace of concentration. As you move, your elbow pushes against your shirt, and it rides up to reveal a strip of the pale skin it covers. You make sure it seems accidental, and take careful note of how the pads of your brother's fingers slide over your skin for half a second too long before being hastily removed. Like they've betrayed him.

Another movement, another mistake, and because you need it and are regaining that look of frustration, another hands-on correction. "This is hard," you murmur, and you're close enough to see the flinch in his face when your breath puffs into his ear. You make your gaze absent and focused over his shoulder, but from the corner of your eye you see the way Itachi bites his lower lip.

Just like he's now regretting having told you to do, you fold your arms over his shoulders to allow for better reach. Itachi's chest is warm when you pretend to slip on the dewy grass beneath you and find yourself closer to your brother than you ostensibly expected. He seems to have stopped breathing. You're not too surprised, because this is now the scene: pressed against each other from knees to shoulders; Itachi's hands on your hips and yours around his neck; warmth in the air between you; your mouth close to your brother's jugular and the fluttering pulse there. Could be a lovers' embrace, though of course the thought would never cross Itachi's baby brother's mind.

Indecent. Filthy. You breathe goosebumps into your brother's neck and he all but jerks away from you to break the moment.

You make sure to look startled, maybe even hurt, and the panic in Itachi's eyes is immediately smothered. Again he summons that small, gentle smile and were this a normal day this is where he would have poked your forehead. He does not. Instead, sweet excuses pour from his mouth and an apology for startling you so; he'd only just remembered an important appointment he had to attend right this moment.

To anyone else, he would be utterly composed and his parting smile perfectly genuine, but to you he is deconstructed. His genius mind turning over itself with horror and guilt and warm, half-formed thoughts he should not entertain.

As you leave the field a few minutes after Itachi's rushed exit, you find yourself quietly whistling.

**to stage a fall**

A fortnight after your victorious (disastrous) training session with your brother, you wait for the night to descend and the house to quiet, and then goes to stand at the door to Itachi's bedroom. You've done that a thousand times before when your childishness wasn't just a plan, and you know your brother won't find it suspicious.

You also know that were he less polite, Itachi would have cursed at the feel of your chakra on the other side of the door. But he will not deny you, because after all, when he left left that training session you waved good-bye with an innocent smile.

The door opens without a sound. You can barely see your brother's thin form in the darkness. "Sasuke?" His voice falls as quiet as the first snow, and you look up at him. You know he can see you clearly, that his eyes are so many times better than yours it's like comparing the smallest of stars to the sun. "Is something the matter?" he asks, and because you know the rise and falls of his voice better than your own, you can hear the moment of hesitance before the he speaks your name.

"I had a nightmare," you say, and twist the hem of your long shirt like you're very embarrassed to be here. Itachi waits. He never could turn you away. "Can I stay with you tonight?"

Itachi doesn't say anything, but when he beckons you into his room, you can see the stiffness in his shoulders. _Ah, brother_. You get into his bed, wonder if his gaze turns to or demonstratively away from your bare legs as you settle yourself. You turn to look at him expectantly, and because you can hear the excuse form before Itachi's mouth begins to move, you give him that smile. The one he likes so much, the one that shines with trust and love, and all of it for him. You don't utilize it often, because you know that every weapon so effective should be sparingly used.

This is the proof of its effectiveness: Itachi seats himself on the edge of the bed. And here is the proof of Itachi's love for you, and lack of trust in himself: he doesn't slide in between the covers, where you are waiting for him.

"What did you dream about?" Itachi asks, and you squirm closer to him, leaning your forehead against his thigh. Your brother is a remarkable shinobi; he doesn't tense any further at the contact. You still feel a ripple in his skin, in his eyes, but that's because you are his brother and can sense these things.

"I don't remember anymore," you say, crinkling your nose into a immature grimace. Itachi smiles down at you, wistfully, tenderly. "I'm sorry for bothering you, 'nii-san," you murmur. Your brother shakes his head in denial, as you knew he would. You are always welcome to approach him.

As you burrow further into his thigh, you make for the bed covers to ride down and reveal the soft flesh of your own upper thigh. You curl an arm over your brother's lap and breathe out in a slow exhale.

"Sasuke," Itachi starts, then pauses. You can hear the tension in him, even though his voice is as even as always. You hum in question, then yawn, rubbing at your eyes. You can almost feel your brother's intentions waver, and whatever he was about to say turns into, "You're tired. I'll stay here until you fall asleep."

Itachi's slim fingers comb through your hair, and you sigh. Your fingers curl into a fist around a handful of your brother's sleep pants, and you turn yourself over to the light slumber of a shinobi veteran. You can still feel your brother at the outskirts of your senses, feel his fingers continuing to comb through your hair. Feel his eyes upon you.

You know your brother is breaking promises to himself, allowing himself to look, and you smile in your sleep.

**and this is how you break him**

It's weeks later and you've traveled several dozen miles into Konoha's deep forests when Itachi gently tells you that here is where you will stop for the night. His eyes flinch from you, harder when you look at him like so: eyes dark and trusting, vulnerable in body and loose-limbed like the child you're not.

"Are we going to sleep together?" you say as your brother unfolds the tent, as he puts your bedrolls next to each other. And you know he hears the words as a baby-brother's question, and that the images in Itachi's mind are of a different kind and that they make your brother's stomach clench. As you brush your fingers against his when accepting the pillow Itachi has brought just for you, you absently wonder if the back of his throat is sour with guilt.

Itachi smiles that gentle smile, but you see him hesitate to lie down beside you. You know your brother could never visit harm upon you; Itachi himself does not. When you turn your head in such a way that the pale column of your throat is exposed, it is in a curious challenge. And so when Itachi murmurs something quiet and soothing about taking first watch, you know he is fleeing you.

Several hours later, Itachi's feather light steps wake you from your slumber, though you feign the deep sleep of the young. The bedroll barely rustles as your brother slides himself into it, and you lie in wait until a full hour has gone by before you begin.

The first is a soft sound, a test. He is not asleep, and you expected that. His eyes are on you now, and you imagine it is with reluctance. But his own discomfort would never stop him from checking up on you, if he thought you might need something from him.

The second is a slight furrow of your eyebrows, and a slight flush to your cheeks. A murmur, a pursing of lips. You know he will see it, because even without the sharingan Itachi's eyes are exceptional. He turns his head, a whisper of sound, and without opening your eyes you can see your brother's expression. Is it a nightmare, he'll wonder, and be prepared to ease you awake.

You moan. It's a tiny sound, just a smidgeon louder than an exhalation. But it is enough. Your brother freezes, and you can almost see his heart stuttering behind his ribcage. He doesn't wake you, and you know that choice is causing him further guilt.

You moan again, the tip of your tongue peeking out between your lips for a brief second. There is the near-silent hiss of an indrawn breath, and so you know Itachi's gaze caught the movement. Of course he did. You smile inwardly, small and satisfied, even as you let the flush in your cheeks deepen. A quiet gasp escapes your lips, and you squirm inside the bedroll.

Itachi seems to have stopped breathing, because the tent is suddenly very quiet but for the small sounds you make. It's not until your hips twitch that you hear movements from your brother again. He is hovering above you, and you sense that his arm is outstretched. To wake you, because that is the right thing to do.

The hand withdraws from where it had been just above your shoulder, and your hips twitch again. You let your face tense, brows furrow deeper and because you've been a shinobi for a very many years, you portray the expression of unconscious pleasure without flaw.

"Sasuke..." Itachi's voice is small and choked, and shame coats your name as your brother breathes it out. "Please," he says, like a prayer, but his voice hitches when your hips slowly set an erratic rhythm. He's watching you, drinking you in, hating himself. It's a sweet victory on your part.

When you finally pretend to climax, the pained sound that escapes your brother makes you wonder if he climaxed with you. Or if he's crying.

**the curtains close**

At 0630 hours the day after their return to the compound, a patrol finds your brother slumped over his katana. You didn't see it, of course, but the image draws itself in your mind like an oil painting: Itachi's long hair loose over his shoulders, black eyes blank and far-seeing in death, the tight grip of slim hands around the sword's hilt. Driven cleanly into his stomach, you hear Tekka inform your father.

It is a glorious moment, and you are not crying.

* * *

**A/N: **This is a first for me, so I'd really appreciate your thoughts. How did the second-person perspective work for you? What did you think of Sasuke's way of taking revenge? What did you think about my portrayal of Sasuke and Itachi?

Thanks to **Against-The-Current** for her helpful thoughts on this!


End file.
